Precise modulation of nickel-molybdenum alloy (MoNi4)/molybdenum dioxide nanowires via a ternary nickel-cobalt-iron complex for enhanced electrochemical overall water splitting

Abstract

Developing renewable and clean energy technologies necessitates the design of efficient bifunctional catalysts that can facilitate electrochemical water splitting without relying on inert metals. This study presents a novel three-step strategy for fabricating nickel cobalt iron (NiCoFe)-modified nickel-molybdenum alloy/molybdenum dioxide (MoNi₄/MoO₂) nanowires on nickel foam (NF) substrates, denoted as NiCoFe-MoNi₄/MoO₂/NF. The synthesized catalyst demonstrates exceptional performance, achieving an impressively low overpotential (13 mV) at 10 mA·cm⁻² current density for the hydrogen evolution reaction (HER) and 230 mV at 50 mA·cm⁻² for the oxygen evolution reaction (OER). Its performance surpasses many noble-metal catalysts, achieving overall water splitting at just 1.51 V under 50 mA·cm⁻². The distinctive one-dimensional (1D) nanostructure and synergistic interplay between the NiCoFe complex and the MoNi₄/MoO₂ framework enhance mass transfer, expose additional active sites, and enhance intrinsic activity, contributing to outstanding efficiency. Incorporating cobalt (Co) and iron (Fe) into the ternary complex greatly improved the efficiencies of both HER and OER, providing a promising approach for developing high-performance, cost-effective bifunctional electrocatalysts and promoting advancements in sustainable energy conversion technologies.